Generally, an elongated fabric material is used for producing fabric products for an elongated fabric material provides more efficient and economical yield than a short fabric material. The edges or hems of an elongated fabric material require hemming to prevent fraying as well as provide a neat appearance.
Japanese Patent Publication No. 57-17554 disclosed an automatic hemming machine for an elongated fabric material, Japanese Patent Publication No. 59-5155 disclosed a hemming apparatus anti Japanese Patent Publication No. 62-19873 disclosed a s.ewing machine with a zigzag controller, all proposed for hemming an elongated fabric material. These prior art apparatus cannot appropriately process the edges or hems for all types of fabric products. Flat fabric products such as scarves, curtains, Japanese style wrapping cloths and towels are conventionally hemmed as schematically shown in FIG. 27 (B) by means of folding a hem portion in three layers, which cannot always be readily and easily performed with a conventional apparatus.
For conventionally forming a hem portion of a fabric material into a layered configuration, a truncated multi-pipe device as shown in FIG. 28 is utilized. A hem portion of an elongated fabric material is fed into the pipe device in the direction shown by an arrow toward a hem stitching machine (not shown) for three-fold rolled hemming as shown in FIG. 27 (B).
Such a truncated pipe device as shown in FIG. 28 may be conveniently utilized to automatically and speedily provide a layered hem portion on a thin and smooth elongated fabric material, however, this hemming method does not adequately apply for processing a thick or undulated fabric material such as one for towels. As shown in FIG. 27 (A), a fabric material 40 for producing towels is an elongated fabric sheet material having piled sections Pa which are separated by non-piled zones along imaginary lines L for cutting. The hem portions of such a fabric material 40 are not uniform in thickness and cannot be readily and smoothly fed into the truncated pipe device.
As FIG. 27 (A) shows, the towel material is provided with fabric sections or regions each having a different thickness. Regions Pa are provided with piles while regions Ta and Tb are plainly woven and have different thicknesses. Regions Ta for providing an aesthetic appearance are to be cut in the center along imaginary lines L. Regions Ta are made thicker than regions Tb and regions Pa are the thickest. Thus the surfaces of the fabric material 40 are undulated.
It is ha;rd to smoothly feed such an undulated towel material 40 into a truncated pipe device for rolled or layered hemming with a hem stitching machine. In addition, the width of the hem portion to be stitched is generally only 5 mm-10 mm, which adds difficulty to partially feeding an elongated fabric material through a truncated pipe device, for a high-speed hemming operation in particular. The truncated pipe device may be enlarged to process a thick or undulated fabric material, however, such an enlarged pipe device then cannot process a thin fabric material adequately.
International Publication No. 92/09734 disclosed a rolled heming apparatus, which processes a hem portion 42 of an elongated fabric material 40 following the steps shown in FIG. 3 (B) (prior art) to provide a layered portion 41 on the hem as shown in step 5. The hem portion 42 consisting of an outer hem portion 42a, middle hem portion 42b and inner hem portion 42c is folded in steps 1-5 to finally provide a layered hem portion 41 in step 5.
According to the disclosed apparatus, it is required to first lift upward the portions 42a and 42b together as shown in step 2, bend the portion 42a inward at a right angle in step 3, bend it again downward in step 4 at a right angle and bend the portion 42b at a right angle together with the portion 42a onto the portion 42c as shown in step 5 to provide a three-layer hem portion 41, which generates considerable mechanical stress onto the apparatus, especially when done at a high speed, possibly causing not only trouble to or malfunctioning of the apparatus but displeasing appearance to the product.
A fabric possesses a degree of shape restoration or repulsion. A fabric material for producing towels has a considerable thickness, which increases the restoration moment. The steps shown in FIG. 3(B) will not be adequately and smoothly carried out on such a thick fabric material as the bent fabric portions, especially when the bent portions are narrow, will generate considerable shape restoration moment.
Accordingjly, it is an object of the present invention to provide a rolled hem forming process that can speedily and smoothly form a three-layer rolled portion 41 on a hem portion 42 of an elongated fabric material 40, thin or thick, by utilizing rounding and pressing means, and not conventional bending or folding means or a conventional truncated multi-piped device, and that without exerting much stress onto the apparatus. It is another object of the present invention to provide a rolled hem forming device utilizing such a process.